When, during World War II, Mr Charles Eames moved to Los Angeles with his new wife Ms Ray Eames (neé Ms Ray Kaiser), the design duo embarked on a career that would define the look of an entire era. Their creative and romantic partnership was of unrivalled influence in the post-war period, thanks to the way they combined an engineer's take on modernism, a joyful sense of optimism and a deeply artistic sensibility. They may now be remembered chiefly as the designers of beautiful furniture, but the film suggests that their talents were far broader than their current legacy suggests.

Mr Jason Cohn is the writer, and co-director, of Eames: The Architect and the Painter, the first feature-length documentary about the couple. He speaks to MR PORTER about how they came to make the film, why no one has a bad word to say about the Eames' designs, and the allure of tweed and corduroy.

What piqued your interest in the Eameses?

When I was in graduate school at UC Berkeley I came across a DVD of the Eames' short films. I had no idea what to make of the films because they didn't fit into any category, but they were very, very beautiful. What struck me was what kind of person gets to make films like this? How do you live a life where you get to make little movies about whatever strikes your fancy?

Were you already familiar with their famous furniture?

Later I became more familiar with their furniture, and the burgeoning interest in mid-century furniture. I first thought to make the film about mid-century modernism as a movement, but then I read a book about Charles and Ray and everything that you'd want to say about mid-century modernism is in their story.

The Eameses moved to Los Angeles from Michigan as soon as they were married; was the location of their office important to their work?

LA was an amazing place to be in the 1940s. It had the aeronautics industry and the film industry, and [the Eameses] tapped into an avant-garde architectural scene and an avant-garde film scene. There was an openness in LA.

What was it that made them famous?

Their designs were very influential, but just as influential was who they were, what they became and how they presented their life together. By the 1960s, in LA, there was a lot of talk of lifestyle, how you create a world and a life that speaks to who you are. That's what the Eames' work was about, the flexibility to craft a lifestyle and an environment that speaks to who you are.

The Eames House, Pacific Palisades, Los Angeles, served as the designers' home and studio

What is so special about the house they built in 1949?

Up to that point modernism had been austere. They demolished that image with their house, it started in the international style, but then they stuffed it with things: flowers, tumbleweeds, crafts and seashells. They customised the modern home to make it personal, representative of who they were, where they'd been and what they'd done. People found that extremely liberating.

Is it fair to see Mr Eames as the engineer and architect, and Ms Eames as the artist/ interior designer?

It's reductive, but probably not too far away from the truth. His background was around engineering, he'd worked in a steel mill; he had a natural facility for technical processes. Ray trained with Hans Hofmann, who was the greatest modern art teacher in the US between the wars, so she had this amazing exposure to painting and sculpture. They complemented each other.

How did the Eameses persuade companies such as IBM to fund their esoteric films, such as Powers of Ten?

Charles was fascinated by mathematics and astrophysics and he believed that kids needed to learn this stuff in order for the US to compete in a global economy. He convinced IBM that it was in its interests that America have an educated workforce. Charles had proximity to the top brass in these companies, he'd sit down with Edwin Land at Polaroid, and when he wanted to make a pitch to IBM he sat down with Tom Watson Jr. Charles had the charisma to maintain those kind of relationships.

The film paints a very positive view of the Eameses, did you decide to ignore their critics?

I don't think it's a particularly adulatory view of them. We showed that Charles was unfaithful to Ray, that he had trouble sharing credit and we do talk about their last project, The World of Franklin and Jefferson exhibition, which was harshly criticised, but it is very hard to find people who are critical of their creative output.

What is it with the bow ties - Mr Eames seems to be wearing one in almost every shot?

Bow ties signified something in the 1950s, 1960s and 1970s. You could be wearing a tie but be a little different, you were wearing the professional uniform, but you weren't wearing a grey flannel suit. He had a very idiosyncratic sense of style, he had his clothes tailored in London, and he'd seek out the finest fabrics - he had a penchant for corduroy and tweed. There are stories of him being in London and spending all day going from haberdasher to haberdasher in search of just the right kind of corduroy.

How would the Eameses feel about their legacy?

The Eames office is working hard to emphasise things beyond the expensive furniture. It would bother them that so many people [associate them with] a piece of furniture that costs £4,000. Their inspiration came out of the Depression and the need for good affordable furniture.

But don't lifestyle choices always involve a bit of shopping?

My sense is that Charles became a bit disenchanted with consumerism. I think his desire to design media experiences came out of this feeling that there was only so much you could do by making a better chair or a better can opener. Taste was changing too, people were more interested in big extravagant luxury and that wasn't really what the Eames office did.